feat: Added server.json to prepare publishing to MCP registry

[christian-kreuzberger-dtx]

Goal: Increase visibility and reach of the dynatrace-mcp-server, by publishing it to the official MCP Registry.

• Created server.json based on https://github.com/modelcontextprotocol/registry/blob/main/docs/guides/publishing/publish-server.md, and tried to publish it to the MCP registry from my local PC (which unfortunately failed due to authentication issues - that will be another story).
• Added some img-shields on top of the README, as those are great visuals and are visible immediately when somebody shows the README (e.g., in VSCode marketplace).
• Moved the disclaimer about support on top.

[github-actions]

📦 Package.json Changes Detected

This PR modifies package.json. Please review the following changes carefully, and tick the following checklist boxes:

Checklist for Reviewers

• Verify that new and/or updated dependencies are necessary and from trusted sources
• Review any script changes for (security) implications
• Verify whether a new version should be released after merging the PR

Package.json Diff

diff --git a/package.json b/package.json
index 4a97a24..29aebec 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,7 @@
 {
   "name": "@dynatrace-oss/dynatrace-mcp-server",
   "version": "0.5.0",
+  "mcpName": "io.github.dynatrace-oss/Dynatrace-mcp",
   "description": "Model Context Protocol (MCP) server for Dynatrace",
   "keywords": [
     "Dynatrace",

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